The coils are linked by the core so are better thought of as a transformer. Any voltage you put on one will appear on the other, and vice-versa. Only series and parallel arrangements will work for a single filtering job; you cannot put them between caps as they will fight the caps and put out essentially the same signal that a single CLC arrangement (using just one winding) would. With the added trouble that, since the windings are fighting each other, current runs up (depending on input ripple voltage) and may cause heating of the choke.

You can use it for filtering two supplies of the same voltage and arrangement (i.e., CLC and CLC, or LC and LC, not mixed), but that is rather redundant. Plus the voltage coupling negates any supposed "crosstalk" issues that some more eccentric power supply "designers" would not consider "kosher".

Originally posted by Sch3mat1c The coils are linked by the core so are better thought of as a transformer. Any voltage you put on one will appear on the other, and vice-versa. ...

Yes! a transformer.

Let me explain what I have & what I want to get from these.

I'm building a line stage pre amp with built-in crossover. To maintain the driving capability of each signal path, it became 4 channels, i.e., 2 for mid-high & 2 for bass. Or you may treat it as 2 pre amps in one chassis....

The gain device is 5842 (one for each channel of course), with output transformers at their plates....

I group them 2 by 2 for the power circuit. 2 tubes in each group share the same rectifier (6X5) & LC filter. Then finally, each tube gets its own big RC.

....

So, here I "refined" the original idea a bit by combining the 2 power circuits into the same iron core. (please see the attached diagram)

I made 2* LCLC into 2* dual-coil choke. Since the final loads for each circuit are mostly identical, and the upstream rectifiers are also the same, so their current & ripple must also be identical. (well, I know our world is not that perfect, I can tolerate)

Making the 2* 1st L in the same core & out of phase, this whole choke looks just like the pri winding of the PP OPT

And the following 2nd L is arranged in the same way.

So, " Any voltage put on one will appear on the other " and they are in the same strength & out of phase, they cancel each other out! Also, like the pri winding of PP OPT, the net flux in the core is nearly 0, so the inductance would be high & can not be saturated.